Ammonium adsorption from wastewater using Malang natural zeolites

Abstract

Zeolite is minerals contain alumina and silica that cross-linked forming a porous tetrahedron shape. This porous structure is enabling zeolites to have advantage as an adsorbent. One of the common technical application of zeolite is as an adsorbent and one of the ion that have high affinity on zeolites is ammonium. Ammonium is an ion form of ammonia and considered as a waste in environment. The objectives of the research were to characterize and study the ammonium adsorption kinetic and isotherm of the Malang natural zeolites. Characterization of the natural zeolites was conducted by X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy-Energy Dispersive of X-ray Spectroscopy (SEM-EDX) and nitrogen physisorption using Brunaurer, Emmet dan Teller (BET) model. According to the XRD patterns, the natural zeolites were dominated by mordenite and clinoptilolite type of zeolite with quartz as impurity phase. The mordenite phase finding was supported by SEM image that showed the needle shape. Analysis using FTIR showed the peaks correspond to functional groups zeolite framework formation. The SEM-EDX showed that the Si/Al ratio of Malang natural zeolite was 5.5. The surface area calculated by nitrogen physisorption was 52 m2/g. Ammonium adsorption test was conducted by 100 ppm of ammonium solution in the batch reactor with variation on adsorption time and mass loading. Ammonium adsorbed onto the zeolites was increased with the adsorption time and mass loading. The kinetic model of Elovich and isotherm model of Langmuir were best fitted with the ammonium adsorption of Malang natural zeolite.